The bovine rotavirus B223 strain was determined to belong to VP7 serotype 10, the bovine rotavirus 678 strain was shown to belong to VP7 serotype 8, and the human rotavirus strains PA151 and PA169 were found to share neutralization specificity with bovine rotavirus VP7 serotype 6 strains. Five single VP7 gene substitution reassortants were generated using a human rotavirus strain ST3 (VP7 serotype 4) and bovine rotavirus strains UK, NCDV, B223, 678, or J2538, each of which had only the VP7 gene from the ST3 strain and the remaining 10 genes from the bovine strain. By cross- neutralization assay, the existence of at least four distinct bovine rotavirus VP4 serotypes was demonstrated. Single gene substitution reassortants were generated between porcine rotavirus strain Gottfried (VP7 serotype 4) and human rotavirus strains D (VP7 serotype 1), DS-1 (VP7 serotype 2), or M (VP7 serotype 3). These reassortants were each comprised of ten genes from the Gottfried strain and a single gene encoding VP7 from the human rotavirus strain. The three porcine x human reassortant viruses as well as parental Gottfried virus have successfully been adapted to grow in DBS-FRhL-2 diploid cells.